When used as a flat panel display device, a liquid crystal display (LCD) device, a plasma display panel (PDP) device, a field emission display (FED) device, and an electroluminescent display (ELD) device each include a flat display panel for displaying images. The flat display panel includes a pair of combined opposite transparent insulated substrates, and a special luminescent or polarized material layer is placed between the pair of substrates. Among these flat panel display devices, the LCD device controls transmittance of liquid crystals via an electric field to display images. In this end, the LCD device includes a display panel having liquid crystal units, a backlight unit for guiding lights to the display panel, and a drive circuit for driving the liquid crystal units. Recently, there are increasing needs for incorporating a touch panel into the LCD device, to sense an area of the touch panel that is touched by a finger or other means and send information related to the touch event. Moreover, for the miniaturization of the device, some components may be shared by the LCD device and the touch panel, however, sharing components between the LCD device and the touch panel may cause adverse interactions therebetween.